Optimum Design And Numerical Simulation Of Deep Pit Support Works About Hayida Health Building

The foundation pit works includes excavation of thefoundation pit, precipitation and set supporting around pitduring underground construction. It require monitor safeguard thesurrounding buildings, structures, roads and underground pipelineto ensure proper and safe construction, which includes exploration,design, construction, environmental monitoring and feedback works.The foundation pit engineering services located almost all civilengineering areas, such as construction workers, irrigation, ports,Highways and Bridges, municipal, underground construction andoffshore engineering works etc.From the 1980s till now, the area of domestic foundationsupport technology has achieved great development, summed up awealth of engineering experience. While many cities in the countryfoundation pit projects happened also many works accident, due tolack of experience and the possession of immature technology, andother factors. These bitter lessons are worth summing up and learn.Despite foundation pit support technical has much monograph,but the most talk about basis of theory, design and calculation,theoretical content. But the books are lack about targeting aspecific object with geological conditions, surroundings andfunctional requirements, how to choose a reasonable both economicand safe, effective and simple support program.In actual projects, the sizes, excavation depth, hydrogeologyconditions, and the surrounding environment with each foundationare not the same. In order to solve complex engineering problems,it often requires integrated applications multiple technologies.So carrying out the design of specific foundation is necessary.This paper gives design program of a real deep foundation pitand carries out Numerical Simulation using the currently morepractical geotechnical software——FLAC,which uses the theoretical knowledge studying in the three yearsand regulations the foundation pit support.The key content and study as follows:First, the foundation pit advances to 20m depth. Theconstruction site is located in the business district, andneighboring buildings are near. The construction operationsparameter is narrow. So it required foundation pit support.Second, the selection of support system will think over thesecurity, the economy, facilitate construction according to thespecial condition. When the program is designed, on the basisdifferent conditions for a variety of support structures, we summedup the select program for the foundation pit works. This design willuse pile anchors support program.Third, basing on the prospecting data, and weighing all thepros and cons of structural endogenous force calculation, thispaper count simply through traditional equivalent beam andShanJianBangNan to get the anchor power and the greatest moment,the imbed depth etc. Using C++ and Visual basic language we compiledprocedures for the convenience of calculations, fast and intuitiveoperation. Using the result of two methods "m" got separately theshift of the support structure, the greatest moment, the largestshear and all anchor forces. Through the optimization of two ways,we selected a suitable calculation for the project——equivalentbeam method, thereby using its their results to design.Four, combining theory and practical experience we designminutely for the support program.(a)Based on the design principles and formula of the anchor,we given preliminary results of the fixed length, the free length,inclination, distance, anchor diameter. InE.Kranz-replacing-walls the stability of anchor is calculated tocorrect the initial design strictly. And it showed the design isstable. Using the results calculated steel for the five anchors.(b)Based on length and parameter of the pile, calculated thecross-sectional area, number the steel etc.(c)The overall design process as follows:According to the size and other data, combining the designresult of pile and anchor, got the number of the piles along longmargin, short margin and the overall number of piles, gave thefurnished tables the anchor and the layout map of the pile, theprofile and node map of the anchor.Five, checking the resist-rise stability and the overallstability of the pit, certificated fully the pit is stable and thedesign is reasonable.Resist-Rise safety factor K=1.31>1.15-1.25, Rise volume are20mm, the overall stability safety factor Fs= 1.496>1. Fullyconsistent with the stability required!Six, the basic principles of numerical simulation methods andLagrangian are introduced. The FLAC3D is given a brief statement.And use the FLAC3D to do the numerical simulation for the excavationand support of the foundation pit. Analysis its findings,conclusions:If there is sufficient soil nature and the physical parametersof support structure, applying FLAC3D procedures to simulate theexcavation and support process can get the distribution ofdisplacement, stress and the stress of anchor, which coincidealmost with the theoretical analysis.The results of the simulation can make out that as a 3D spacestructures with long, wide and deep-size, its deformation hasapparently space effect, its support system design is a the questionof complex three-dimensional space. Properly increasing thepile-length of center of the pit wall pillar, or reducing the lengthof pit wall turning can make it more reasonable, and give full playto pile the support results.